Raw Dihuang has the effect of clearing heat and cooling blood, while cooked Dihuang has the effect of tonifying blood and nourishing yin.
Raw Dihuang is the tuberous root of Dihuang, a plant in the family of Ginseng, which is sweet, bitter and cold in nature, and enters the heart, liver and kidney meridians. It has the effect of clearing heat and cooling blood, nourishing yin and generating body fluid. It is clinically used in the treatment of yin deficiency and fever, thirst, vomiting blood, epistaxis, coughing blood, hematochezia, menstrual disorders, fetal restlessness, and constipation due to yin injury. Adverse reactions and contraindications are not clear.
Radix Rehmanniae Praeparata is the concocted product of Radix Rehmanniae Praeparata, which is sweet in taste, slightly warm in nature, and belongs to the liver and kidney meridians. It has the effect of tonifying blood, nourishing yin, benefiting essence and filling in marrow. Clinically, it is used to treat blood deficiency, menstrual disorders, yin deficiency of the liver and kidney, lumbar and knee soreness and weakness, night sweating (sweating abnormally after going to sleep and stopping after waking up), spermatorrhea, etc. It is also used in the treatment of blood stagnation, phlegm, and abdominal pain. It is contraindicated for those who have stagnant qi and phlegm, abdominal distension and pain, and loose food and stools (thin and unformed feces).
When taking Chinese herbs, it is necessary to do so under the diagnosis and treatment of a professional Chinese medicine practitioner, do not self-medicate, so as not to cause physical discomfort.